.box{
    position: relative;
    width: 100px;
    height: 100px;
    background-color: greenyellow;
    margin-bottom: 10px;
    text-align: center;
    line-height: 100px;
}

.success{
    background-color: greenyellow;
    z-index: 1000;
}

.danger{
    background-color: #FF0000;
    z-index:100;
}